TW202212408A - Liquid crystalline polyester liquid composition, liquid crystalline polyester film, laminate, and method for manufacturing liquid crystalline polyester film - Google Patents

Abstract

The present invention relates to a liquid crystalline polyester liquid composition that comprises: a liquid crystalline polyester (A) which is soluble in aprotic solvents; an aprotic solvent (S); and a fluororesin (B) which has a melting point of 305 DEG C or lower.

Description

Liquid crystal polyester liquid composition, liquid crystal polyester film, laminate, and method for producing liquid crystal polyester film

The present invention relates to a liquid crystal polyester liquid composition, a liquid crystal polyester film, a laminate, and a method for producing the liquid crystal polyester film. In this case, priority is claimed based on Japanese Patent Application No. 2020-088885 filed in Japan on May 21, 2020, the content of which is incorporated herein.

Insulating materials are used in printed circuit boards on which electronic components are mounted. In recent years, with the development of communication systems and the like, further improvements in physical properties such as dielectric properties are expected for insulating materials. As a method of improving the dielectric properties of the insulating material, it is performed using a fluororesin having good dielectric properties. For example, according to Patent Document 1, a sheet formed by melt-kneading a resin composition to which a carbonyl-containing group-containing fluoropolymer, a liquid crystal polymer, or the like is added has excellent electrical properties, shock resistance, and mechanical strength. . [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2018-177931

[Problems solved by the invention]

However, in the insulating material to which the fluororesin is added, there is a problem that the adhesion strength to the copper foil is lowered.

In order to solve the above-mentioned problems, the present invention aims to provide a liquid crystal polyester liquid composition capable of producing a film having excellent adhesion strength with copper foil and excellent dielectric properties. Moreover, this invention aims at providing the manufacturing method of the liquid crystal polyester film, the laminated body, and the liquid crystal polyester film which are excellent in the adhesion strength with copper foil and dielectric property. [Means to solve the problem]

In order to solve the above-mentioned problems, the present inventors conducted detailed examinations and found that a liquid crystal polyester that is soluble in an aprotic solvent is used and that a film forming method capable of producing a film having excellent isotropic properties is applicable. When a fluororesin having a melting point of 305° C. or less is used in combination, the adhesion strength to the copper foil can be maintained and the dielectric properties can be improved, and the present invention has been completed. That is, the present invention has the following aspects.

[1] A liquid crystal polyester liquid composition comprising a liquid crystal polyester (A) soluble in an aprotic solvent, an aprotic solvent (S), and a fluororesin (B) having a melting point of 305° C. or lower. [2] The liquid crystal polyester liquid composition according to the above [1], wherein the liquid crystal polyester (A) contains an amide bond. [3] The aforementioned liquid crystal polyester (A) contains the aforementioned [1] or [ 2] The liquid crystal polyester liquid composition according to the description. (A1) -O-Ar1-CO- (A2) -CO-Ar2-CO- (A3) -X-Ar3-Y- (wherein Ar1 represents 1,4-phenylene, 2,6-naphthalene di base or 4,4'-diphenylene, Ar2 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthalene diyl, Ar3 represents 1,4-phenylene or 1, 3-phenylene, X represents -NH-, Y represents -O- or -NH-). [4] The aforementioned [3] wherein the aforementioned Ar1 is a 2,6-naphthalene diyl group, the aforementioned Ar2 is a 1,3-phenylene group, the aforementioned Ar3 is a 1,4-phenylene group, and the aforementioned Y is -O- Liquid crystal polyester liquid composition. [5] The content ratio of the liquid crystal polyester (A) is 10 mass % or more and 90 mass % or less with respect to the total content of the solid content of the liquid crystal polyester liquid composition, and the content of the fluororesin (B) is The liquid crystal polyester liquid composition according to any one of the above [1] to [4] in which the ratio is 10 mass % or more and 90 mass % or less. [6] The liquid crystal polyester liquid composition according to any one of the above [1] to [5], which further contains an inorganic filler (C). [7] With respect to the total content of the solid content of the liquid crystal polyester liquid composition, the content of the liquid crystal polyester (A) is 25% by mass to 40% by mass, and the content of the fluororesin (B) is The liquid crystalline polyester liquid composition described in the above [6] with a ratio of 25 mass % or more and 40 mass % or less, and a content ratio of the inorganic filler (C) being 20 mass % or more and 50 mass % or less. [8] The liquid crystal polyester liquid composition according to the aforementioned [6] or [7] in which the inorganic filler (C) is a silica filler. [9] The liquid crystal polyester liquid composition according to any one of the above [1] to [8], wherein the crystallite size of the fluororesin (B) is 2.9×10 ⁻⁸ m or less. [10] The aforementioned fluororesin (B) is selected from the group consisting of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (perfluoroalkoxyalkane, PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoroethylene At least one kind of fluorine grouped by propylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer and polyvinylidene fluoride (PVDF) The liquid crystal polyester liquid composition according to any one of the above [1] to [9] of the resin. [11] Any one of [1] to [10] wherein the content of the liquid crystal polyester (A) is 0.01 parts by mass to 100 parts by mass relative to 100 parts by mass of the aprotic solvent (S) The liquid crystal polyester liquid composition. [12] The liquid crystal polyester liquid composition according to any one of the above [1] to [11], wherein the aprotic solvent (S) is N-methylpyrrolidone. [13] A liquid crystal polyester film containing a liquid crystal polyester (A) and a fluororesin (B) having a melting point of 305° C. or lower, wherein the liquid crystal polyester (A) contains an amide bond. [14] The liquid crystal polyester (A) contains a structural unit represented by the following formula (A1), a structural unit represented by the following formula (A2), and a structural unit represented by the following formula (A3), as described in the aforementioned [13] liquid crystal polyester film. (A1) -O-Ar1-CO- (A2) -CO-Ar2-CO- (A3) -X-Ar3-Y- (wherein Ar1 represents 1,4-phenylene, 2,6-naphthalene di base or 4,4'-diphenylene, Ar2 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthalene diyl, Ar3 represents 1,4-phenylene or 1, 3-phenylene, X represents -NH-, Y represents -O- or -NH-). [15] A laminate comprising a metal layer and the liquid crystal polyester film according to [13] or [14] laminated on the metal layer. [16] A laminate comprising a metal layer and a liquid crystal polyester film formed by applying the liquid crystal polyester liquid composition according to any one of the above [1] to [12] on the metal layer. [17] Coating the liquid crystal polyester liquid composition according to any one of the above [1] to [12] on a support, and removing the aprotic solvent (S) from the liquid crystal polyester liquid composition, A method for producing a liquid crystal polyester film in which a heat treatment is performed to obtain a liquid crystal polyester film. [Effect of invention]

According to the present invention, it is possible to provide a liquid crystal polyester liquid composition capable of producing a film having excellent adhesion strength with copper foil and excellent dielectric properties. Moreover, according to this invention, the manufacturing method of the liquid crystal polyester film, the laminated body, and the liquid crystal polyester film excellent in the adhesion strength with copper foil and dielectric property can be provided.

[The form of carrying out the invention]

Embodiments of the liquid crystal polyester liquid composition, the liquid crystal polyester film, the laminate, and the method for producing the liquid crystal polyester film of the present invention will be described below.

≪Liquid composition of liquid crystal polyester≫ The liquid crystal polyester liquid composition of the embodiment contains a liquid crystal polyester (A) soluble in an aprotic solvent, an aprotic solvent (S), and a fluororesin (B) having a melting point of 305°C or lower. The term "liquid composition" in this specification refers to a solution or dispersion that is liquid at normal temperature and pressure (25° C., 1 atm). The case of a dispersion liquid means a dispersion liquid in which the dispersion medium is a liquid at normal temperature and normal pressure (25° C., 1 atm). A dispersion liquid means what disperse|distributes the solid content which does not melt|dissolve in a solution. The term "solid content" in this specification refers to components other than the solvent contained in the liquid composition. Examples of the dispersed solid content include the above-mentioned fluororesin (B), the below-mentioned inorganic filler (C), and the like. As a solvent, it corresponds, for example to the aprotic solvent (S) mentioned later.

In the liquid composition of the embodiment, the content ratio of the solid content is not particularly limited with respect to the total mass of the liquid composition, and may be 0.5 mass % or more, or 0.5 mass % or more and 80 mass %. % or less, 1 mass % or more and 70 mass % or less, or 5 mass % or more and 50 mass % or less.

Hereinafter, the liquid crystal polyester liquid composition according to one embodiment of the present invention is also simply referred to as the "liquid composition" of the embodiment.

<(A) Ingredient> (A) Component is a liquid crystal polyester soluble in an aprotic solvent (S). (A) When the liquid composition of the embodiment is formed into a thin film on a metal foil, the adhesion strength with the metal foil can be improved, and the mechanical strength can be improved.

The liquid crystal polyester is a liquid crystal polyester that exhibits liquid crystallinity in a molten state, and it is preferably one that can be melted at a temperature of 450° C. or lower. In addition, the liquid crystal polyester may be a liquid crystal polyester imide, a liquid crystal polyester ether, a liquid crystal polyester carbonate, or a liquid crystal polyester imide. The liquid crystal polyester is preferably a wholly aromatic liquid crystal polyester having only a structural unit derived from an aromatic compound as a raw material monomer. In addition, the term "derived from" in the present specification means that the chemical structure of the functional group imparted to the polymerization changes during the polymerization of the raw material monomers, but other structural changes do not occur.

Whether or not the liquid crystal polyester is soluble in the aprotic solvent (S) can be confirmed by conducting the following test.

·experiment method After stirring 5 parts by mass of the liquid crystal polyester in 95 parts by mass of an aprotic solvent at a temperature of 180° C. using an anchor blade for 6 hours under stirring conditions of 200 rpm, it was cooled to room temperature. Next, after filtering using a membrane filter with a pore size of 5 μm and a pressure filter, the residue on the membrane filter was confirmed. At this time, it was judged that it was soluble in an aprotic solvent when the solid content was not confirmed. When a solid component was confirmed, it was judged that it did not dissolve in an aprotic solvent. The solid content can be confirmed by microscope observation.

The liquid crystal polyester (A) preferably contains an amide bond. Since the liquid crystal polyester (A) contains an amide bond, the adhesion strength with the copper foil can be improved when it is laminated with the copper foil as a film.

As an example of the liquid crystal polyester (A) which contains an amide bond and is soluble in an aprotic solvent, one containing a structural unit represented by the following formula (A1), a structural unit represented by the following formula (A2), and A structural unit represented by the following formula (A3).

(A1) -O-Ar1-CO- (A2) -CO-Ar2-CO- (A3) -X-Ar3-Y- (In the formula, Ar1 represents 1,4-phenylene, 2,6-naphthalenediyl or 4,4'-diphenylene, and Ar2 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthalene diyl, Ar3 represents 1,4-phenylene or 1,3-phenylene, X represents -NH-, Y represents -O- or -NH-).

In the present embodiment, it is particularly preferred that the aforementioned Ar2 is a 1,3-phenylene group. When Ar2 is a 1,3-phenylene group, the dissolution in an aprotic solvent becomes more favorable. This is presumably caused by the introduction of a curved structure into the polymer when Ar2 is 1,3-phenylene.

In the present embodiment, the dissolution to the aprotic solvent is good, and the above-mentioned Ar1 is 2, 6 from the viewpoint that the adhesion strength with the copper foil and the dielectric properties can be easily expressed when the film and the copper foil are laminated. -Naphthalene diyl, the aforementioned Ar2 is 1,3-phenylene, the aforementioned Ar3 is 1,4-phenylene, and the aforementioned Y is -O-.

When the liquid crystalline polyester has all kinds of structural units represented by the above formulae (A1) to (A3), the ratio of the preferred content of each structural unit in the liquid crystalline polyester can be exemplified below.

The content of the structural unit represented by the above formula (A1) relative to the total content of all the structural units constituting the liquid crystal polyester (A) (by dividing the mass of each structural unit constituting the liquid crystal polyester by the respective structural unit) In terms of the formula quantity, the equivalent amount (mol) of the material of each structural unit is obtained, and the value is obtained by summing them up), which is preferably 30 mol% or more and 80 mol% or less, and 40 mol% or more. 70 mol% or less is better, more preferably 45 mol% or more and 65 mol% or less. When the content of the structural unit (A1) is below the above upper limit value, the solubility of the solvent tends to be good, and when it is more than the above lower limit value, the liquid crystallinity tends to be good.

The content of the structural unit represented by the above formula (A2) is preferably 10 mol % or more and 35 mol % or less with respect to the total content of all structural units constituting the liquid crystal polyester (A), and 15 mol % or less. Molar % to 30 mol % is preferred, and 17.5 mol % to 27.5 mol % is more preferred. When the content of the structural unit (A2) is below the above upper limit value, the liquid crystallinity tends to be good, and when it is more than the above lower limit value, the solubility in a solvent tends to be good.

The content of the structural unit represented by the above formula (A3) is preferably 10 mol % or more and 35 mol % or less with respect to the total content of all structural units constituting the liquid crystal polyester (A), and 15 mol % or less. Molar % to 30 mol % is preferred, and 17.5 mol % to 27.5 mol % is more preferred. When the content of the structural unit (A3) is below the above upper limit value, the liquid crystallinity tends to be good, and when it is more than the above lower limit value, the solubility in the solvent tends to be good.

In addition, the content of the structural unit (A2) in the so-called liquid crystal polyester (A) and the content of the structural unit (A3) are preferably equal, but when the content is different, the structural unit (A2) and the structural unit ( The difference in the content of A3) is preferably 10 mol % or less. By this difference, the degree of polymerization of the liquid crystal polyester can be controlled.

The ratio of the preferable content of each structural unit in the liquid crystal polyester (A), relative to the total content of all the structural units constituting the liquid crystal polyester (A), the content of the structural unit represented by the above formula (A1) The content of the structural unit shown in the above formula (A2) is preferably 10 mol% or more and 35 mol% or less, and the structure shown in the above formula (A3) is preferred. The content of the unit is preferably more than 10 mol% and less than 35 mol%.

The ratio of the preferable content of each structural unit in the liquid crystal polyester (A), relative to the total content of all the structural units constituting the liquid crystal polyester (A), the content of the structural unit represented by the above formula (A1) It is better to be more than 40 mol % and less than 70 mol %, and the content of the structural unit shown in the above formula (A2) is preferably more than 15 mol % and less than 30 mol %. The content of the indicated structural unit is more preferably 15 mol % or more and 30 mol % or less.

The ratio of the preferable content of each structural unit in the liquid crystal polyester (A), relative to the total content of all the structural units constituting the liquid crystal polyester (A), the ratio of the structural units represented by the above formula (A1) More preferably, the content of the structural unit shown in the above formula (A2) is more than 17.5 mol% and below 27.5 mol%. The above formula (A3) The content of the structural unit shown by ) is more preferably 17.5 mol % or more and 27.5 mol % or less.

The structural unit (A1) can be derived from, for example, an aromatic hydroxycarboxylic acid. The structural unit (A2) can be derived from, for example, a structural unit of an aromatic dicarboxylic acid. The structural unit (A3) can be derived from, for example, an aromatic diamine or an aromatic amine having a phenolic hydroxyl group. For the component (A), an ester or amide-forming derivative of the above-mentioned structural unit may be used in place of the above-mentioned structural unit.

Examples of ester-forming derivatives of carboxylic acids include those with high reactivity such as acid chlorides and acid anhydrides that promote the reaction of forming polyesters as carboxyl groups, and those with high reactivity such as those formed by transesterification reactions as carboxyl groups Esters, such as alcohols or ethylene glycol, form esters, etc. As an ester-forming derivative of a phenolic hydroxyl group, for example, a phenolic hydroxyl group can be exemplified by those that form an ester with a carboxylic acid. As an amide-forming derivative of an amine group, for example, an amine group can be exemplified by those which form an amide with carboxylic acids.

Although the following can be illustrated as a structural unit of (A) component used for this embodiment, it is not limited to these.

As the structural unit represented by the formula (A1), for example, a structural unit derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4-hydroxy-4'-biphenylcarboxylic acid, etc., and two types of The above-mentioned structural units may also be included in the total structural units. Among these structural units, a structural unit derived from 6-hydroxy-2-naphthoic acid is preferred.

Examples of the structural unit represented by the formula (A2) include structural units derived from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and the like, and two or more of the aforementioned structural units may be contained in in the entire structural unit. Among these structural units, a structural unit derived from isophthalic acid is preferable from the viewpoint of solubility in a solvent.

Examples of the structural unit represented by the formula (A3) include 3-aminophenol, 4-aminophenol, 1,4-phenylenediamine, 1,3-phenylenediamine, 4-aminobenzoic acid, As for the structural units such as p-acetaminophenol, etc., two or more of the above-mentioned structural units may be included in all the structural units. Among these structural units, those derived from 4-aminophenol or p-acetamidophenol are preferred from the viewpoint of reactivity.

The liquid crystal polyester which is soluble in an aprotic solvent may be a liquid crystal polyester containing a structural unit derived from p-acetaminophenol. The liquid crystal polyester soluble in an aprotic solvent may be composed of a structural unit derived from 6-hydroxy-2-naphthoic acid, a structural unit derived from p-acetaminophenol, and a structural unit derived from isophthalic acid. of liquid crystal polyester.

Although the method for producing the component (A) used in the present embodiment is not particularly limited, for example, an aromatic hydroxy acid corresponding to the structural unit (A1) and an aromatic group having a phenolic hydroxyl group corresponding to the structural unit (A3) can be mentioned. The phenolic hydroxyl group or amine group of aromatic amines and aromatic diamines is acylated by excess fatty acid anhydride to obtain acylation products, and the obtained acylation products and aromatic dicarboxylic acids corresponding to the structural unit (A2) are esterified and fermented A method of performing melt polymerization by amine exchange (polycondensation), etc. (refer to Japanese Patent Laid-Open No. 2002-220444 and Japanese Patent Laid-Open No. 2002-146003).

The addition amount of fatty acid anhydride is preferably 1.0 to 1.2 times equivalent, more preferably 1.05 to 1.1 times equivalent, relative to the sum of the phenolic hydroxyl group and the amino group in the acylation reaction. If the amount of fatty acid anhydride added is too small, the amides and raw material monomers will be sublimated during transesterification and amide exchange (polycondensation), and the reaction system tends to be blocked easily. The coloration of ester has a tendency to become prominent.

The acylation reaction is preferably carried out at 130 to 180° C. for 5 minutes to 10 hours, and preferably at 140 to 160° C. for 10 minutes to 3 hours.

The fatty acid anhydride used in the acylation reaction is not particularly limited, and examples thereof include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, 2ethylhexane anhydride, monochloroacetic anhydride, Dichloroacetic anhydride, trichloroacetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride , β-bromopropionic anhydride, or the like, and a mixture of two or more of these can also be used. In this embodiment, acetic anhydride, propionic anhydride, butyric anhydride, or isobutyric anhydride is preferred, and acetic anhydride is more preferred.

In the case of transesterification and amide exchange (polycondensation), the amide group of the amide compound is preferably 0.8 to 1.2 times the equivalent of the carboxyl group.

Transesterification and amide exchange (polycondensation) are preferably performed at a rate of 0.1 to 50°C/min while raising the temperature to 400°C, and performed at a rate of 0.3 to 5°C/minute while raising the temperature to 350°C. better.

When transesterification or amide exchange (polycondensation) of an amide compound and a carboxylic acid is carried out, the fatty acid and unreacted fatty acid anhydride as by-products are preferably evaporated and distilled out of the system.

In addition, the acylation reaction, transesterification and amide exchange (polycondensation) can also be carried out in the presence of a catalyst. As the catalyst, known catalysts for polyester polymerization in the past can be used, for example, magnesium acetate, first tin acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, trisodium acetate, etc. Metal salt catalysts such as antimony oxide, organic compound catalysts such as N,N-dimethylaminopyridine, N-methylimidazole, etc. Among these catalysts, it is preferable to use a heterocyclic compound containing two or more nitrogen atoms, such as N,N-dimethylaminopyridine and N-methylimidazole (refer to JP-A-2002-146003 ). ). The catalyst is usually charged when monomers are charged, and does not need to be removed after carboxylation, and the transesterification can be directly performed when the catalyst is not removed.

The polycondensation by transesterification and amide exchange is usually carried out by melt polymerization, but melt polymerization and solid phase polymerization may be used in combination. In the solid-phase polymerization, the polymer is taken out from the melt polymerization step, and then pulverized into powder or flakes, and is preferably carried out by a known solid-phase polymerization method. Specifically, for example, a method of performing heat treatment in a solid-phase state at 20 to 350° C. for 1 to 30 hours under an inert atmosphere such as nitrogen can be mentioned. The solid-phase polymerization may be carried out in a state of being stirred, or in a state of standing without stirring. Furthermore, by having an appropriate stirring mechanism, the melt polymerization tank and the solid phase polymerization tank can be set in the same reaction tank. After the solid-phase polymerization, the obtained liquid crystal polyester can be pelletized and molded by a known method. The production of the liquid crystal polyester can be performed using, for example, a sorting apparatus, a continuous apparatus, or the like.

The content of the component (A) may be 10 mass % or more and 90 mass % or less, 15 mass % or more and 50 mass % or less, with respect to the total solid content of the liquid composition of the embodiment. It may be 25 mass % or more and 40 mass % or less. By using the liquid composition containing (A) component in the said numerical range, the adhesive strength and dielectric property of the produced liquid crystal polyester film and copper foil can be improved easily.

＜(S)component＞ (S) component is an aprotic solvent. Aprotic solvents have the advantage of being less corrosive and easier to handle. In the present embodiment, the term "aprotic solvent" refers to a solvent containing an aprotic compound. In the present embodiment, examples of the aprotic solvent include 1-chlorobutane, chlorobenzene, 1,1-dichloroethane, 1,2-dichloroethane, chloroform, 1,1,2, Halogen-based solvents such as 2-tetrachloroethane, ether-based solvents such as diethyl ether, tetrahydrofuran, and 1,4-dioxane, ketone-based solvents such as acetone and cyclohexanone, ester-based solvents such as ethyl acetate, γ - Lactone-based solvents such as butyrolactone, carbonate-based solvents such as ethylidene carbonate and propylidene carbonate, amine-based solvents such as triethylamine and pyridine, and nitrile-based solvents such as acetonitrile and succinonitrile , N,N'-dimethylformamide, N,N'-dimethylacetamide, tetramethylurea, N-methylpyrrolidone and other amide solvents, nitromethane, nitro Nitro-based solvents such as benzene, sulfide-based solvents such as dimethylsulfoxide and cyclobutane, and phosphoric acid-based solvents such as hexamethylphosphoric acid amide and tri-n-butylphosphoric acid, etc., may also be used in two or more kinds of these. mixture.

Among these, an aprotic compound having no halogen atom can be used from the viewpoint of good influence on the environment, and a solvent having a dipole moment of 3 or more and 5 or less is preferably used from the viewpoint of solubility. Specifically, an amide-based solvent such as N,N'-dimethylformamide, N,N'-dimethylacetamide, tetramethylurea, and N-methylpyrrolidone, or γ-butyrolactone is used. Lactone-based solvents such as esters can be preferably used, and N,N'-dimethylformamide, N,N'-dimethylacetamide, or N-methylpyrrolidone can be preferably used.

In the liquid composition of the embodiment, the ratio of the content of the component (S) to the total mass of the liquid composition is to reduce the viscosity of the liquid composition to facilitate coating on the support. From a viewpoint, it may be 20 mass % or more, 20 mass % or more and 99 mass % or less, or 50 mass % or more and 95 mass % or less.

In the liquid composition of the embodiment, the content of the liquid crystal polyester (A) is preferably 0.01 part by mass or more and 100 parts by mass or less, preferably 1 part by mass or more and 70 parts by mass with respect to 100 parts by mass of the aprotic solvent (S). It is preferably not more than 5 parts by mass, and more preferably not less than 5 parts by mass and not more than 40 parts by mass.

In the embodiment, when the content of the liquid crystalline polyester (A) is in the above-mentioned range, the coating of the metal foil or the like with respect to the support becomes easy. The content of the liquid crystal polyester (A) can be appropriately adjusted by the desired film thickness within the above range.

<(B) component> The component (B) is a fluororesin having a melting point of 305°C or lower. The "fluororesin" refers to a resin containing a fluorine atom in the molecule, and examples thereof include polymers having a structural unit containing a fluorine atom. Examples of the fluororesin (B) include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), and ethylene-tetrafluoroethylene copolymer compound, ethylene-chlorotrifluoroethylene copolymer, polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (perfluoroalkoxyalkane, PFA), etc. The fluororesin (B) is selected from the group consisting of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (perfluoroalkoxyalkane, PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylidene At least one fluororesin grouped by copolymer (FEP), polychlorotrifluoroethylene (PCTFE), ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer and polyvinylidene fluoride (PVDF) is good. The aforementioned fluororesin (B) is preferably a perfluoroalkoxyalkane (PFA) having a melting point of 305° C. or lower. The liquid composition of the embodiment may contain two or more fluororesins.

Fluorine resins contain fluorine atoms in their molecules, and can make films containing fluorine resins excellent in dielectric properties.

The melting point of the fluororesin (B) according to the embodiment is 305°C or lower, preferably 303°C or lower, and more preferably 301°C or lower.

When the melting point of the fluororesin (B) is equal to or less than the above-mentioned upper limit value, the characteristic of the adhesion strength between the film containing the fluororesin (B) and the copper foil can be improved. Although this mechanism is not clarified, it is considered that the lowering of the melting point of the fluororesin reflects the lowering of the molecular weight of the fluororesin, thereby improving the adhesion to the copper foil.

The lower limit of the melting point of the fluororesin (B) of the embodiment may be 280°C or higher, 290°C or higher, or 295°C or higher in consideration of practicality in the application for obtaining heat resistance.

The upper limit value and the lower limit value of the melting point of the fluororesin (B) according to the embodiment can be freely combined. As an example of the numerical range of the melting point of the fluororesin (B), it may be 280°C or more and 305°C or less, 290°C or more and 303°C or less, or 295°C or more and 301°C or less.

The melting point of the fluororesin (B) is a value obtained by measuring the endothermic absorption peak of differential scanning calorimetry (DSC) in accordance with JISK 6935.

The melting point of the fluororesin (B) can be adjusted by controlling the molecular weight of the fluororesin in addition to selecting the raw material of the fluororesin. The molecular weight of the fluororesin can be obtained as a desired value by appropriately adjusting the polymerization rate, polymerization time, and the like during production.

In the fluororesin (B) according to the embodiment, the crystal particle size is preferably 2.9×10 ^-8 m or less, more preferably 2.7×10 ^-8 m or less, more preferably 2.5×10 ^-8 m or less good.

By setting the crystal sub-size of the fluororesin (B) to be equal to or less than the above-mentioned upper limit value, the characteristics of the adhesion strength between the film containing the fluororesin (B) and the copper foil can be improved. Although the mechanism has not been clarified, it is considered that when the crystallite size of the fluororesin is small, the decrease in the molecular weight of the fluororesin is reflected, and thereby, it is considered that the adhesion to the copper foil can be improved.

The lower limit value of the crystal size of the fluororesin (B) of the embodiment may be, for example, 2.0×10 ^-8 m or more, 2.1×10 ^-8 m or more, or 2.2×10 ^-8 m or more. .

The upper limit value and the lower limit value of the crystal subsize of the fluororesin (B) according to the embodiment can be freely combined. As an example of the numerical range of the crystal sub-size of the fluororesin (B), it may be 2.0×10 ^-8 m or more and 2.9×10 ^-8 m or less, or 2.1×10 ^-8 m or more and 2.7×10 ^-8 m Below, it may be 2.2×10 ^-8 m or more and 2.5×10 ^-8 m or less.

The crystal sub-size of the fluororesin (B) can be performed by the following method using a wide-angle X-ray scattering (WAXS: Wide Anle X-ray Scattering) measuring apparatus. The fluororesin powder sample is sandwiched by a bag-shaped polyimide film, and the X-beam size is adjusted to be smaller than the size of the sample. The wavelength of the X-ray was taken as λ=1.5418Å, and the measurement was carried out in the range of the diffraction angle 2θ=5° to 30°. For the fluororesin powder sample, X-rays were incident in the thickness direction of the polyimide film, and transmission X-ray intensity measurement and WAXS measurement were performed to obtain transmission X-ray intensity A _S and WAXS scattering intensity _IS . Transmission X-ray intensity measurement and WAXS measurement were performed under the same conditions except for the non-fluorine-containing resin powder to obtain background transmission X-ray intensity _AB and WAXS scattering intensity _IB . According to the following formula (1), the transmitted X-ray intensity correction and background control are performed to obtain the corrected WAXS scattering intensity I _C . I _C =I _S /A _S -I _B /A _B (1)

The measurement method of the crystal sub-size by X-ray diffraction can be carried out as follows. The crystal particle size (Å) of the fluororesin powder can be determined by the diffraction absorption peak of the Debye ring obtained by wide-angle X-ray diffraction (the one with the absorption peak top in the range of the diffraction angle 2θ=17.93±0.2° is regarded as the diffraction absorption peak. The half-value width (β) of the scattering intensity in ) can be calculated by the Scherrer formula of the following formula (2). D=K･λ/βcosθ ･･･(2) In the formula, D is the crystal size, λ is the measured X-ray wavelength, β is the half-value amplitude (radian), θ is the diffraction angle, and K is the Scherrer constant (0.94).

From the same viewpoint, in the X-ray diffraction analysis of the fluororesin (B) of the embodiment, the half value width of the absorption peak having the absorption peak at the diffraction angle 2θ=17.93±0.2° is preferably 0.29 to 0.43, It is preferably 0.31-0.41, and more preferably 0.33-0.39.

A fluororesin that satisfies the above-mentioned values of melting point, crystal size, and half value width can be used by a vendor, for example, EA2000 manufactured by AGC, etc. can be used.

In addition, since the liquid composition of the embodiment contains the fluororesin (B), the water absorption rate when used as a film can be improved.

The fluororesin contained in the liquid composition of the embodiment may be a powder. The volume average particle diameter of the fluororesin may be 0.1 μm or more and 30 μm or less, 0.5 μm or more and 10 μm or less, or 1 μm or more and 5 μm or less. When the volume average particle diameter of the fluororesin is within the above-mentioned range, it is preferable because the surface smoothness when used as a film can be excellent. The volume average particle diameter of the fluororesin can be measured by a wet method using a laser diffraction/scattering particle size distribution measuring apparatus using water as a dispersion medium.

Although the shape of the said fluororesin contained in the liquid composition of embodiment is not specifically limited, For example, a spherical shape, a block shape, a fibrous shape, or a scaly shape can be used. In particular, spherical or block-shaped ones are preferable from the viewpoint of excellent dispersibility in the liquid crystal polyester liquid composition.

The mass ratio (solid content) [(A) component:(B) component] of (A) component and (B) component contained in the liquid composition of the embodiment may be, for example, 9:1 to 1:9, It can also be 5:1 to 1:5, or 3:2 to 2:3. By using the liquid composition containing (A) component and (B) component in the said ratio, the adhesive strength, dielectric property, and water resistance of the produced liquid crystal polyester film and copper foil can be easily improved.

The content of the component (B) may be 10 mass % or more and 90 mass % or less, 15 mass % or more and 50 mass % or less, or 25 mass % with respect to the total solid content of the liquid composition. More than 40 mass % or less. By using the liquid composition containing (B) component in the said numerical range, the adhesive strength, dielectric property, and water resistance of the produced liquid crystal polyester film and copper foil can be improved easily.

The liquid composition of the embodiment may contain (A) component, (B) component, and (S) component. As a preferable example of the compounding ratio of each component in the composition, the content ratio of the aforementioned (A) component is 10 mass % or more and 90 mass % or less with respect to the total content of the solid content of the liquid composition. , (B) The content rate of a component is 10 mass % or more and 90 mass % or less. Moreover, as an example of the combination of these numerical ranges, for example, the numerical value exemplified above as an example of the content ratio of each component can be combined freely.

＜Other ingredients＞ The liquid composition of the embodiment may contain components other than components (A), (B), and (S) as necessary, such as fillers, antioxidants, heat stabilizers, ultraviolet absorbers, electrification Additives such as inhibitors, surfactants, flame retardants, and colorants, and resins not equivalent to (A) components and (B) components.

Examples of fillers include inorganic fillers (C) such as silicon dioxide, aluminum oxide, titanium oxide, barium titanate, strontium titanate, aluminum hydroxide, and calcium carbonate; and cured epoxy resins, cross-linked benzene, etc. And organic fillers such as guanamine resin and cross-linked acrylic resin. As the inorganic filler (C), a silica filler is preferable from the viewpoint of increasing the dielectric loss tangent of the liquid crystal polyester film.

Although the technique of increasing the dielectric loss tangent by adding a silica filler has been known in the past, when liquid crystal polyester is used together, there is a problem that the adhesion strength to the copper foil is lowered. However, in the above-mentioned liquid composition containing the fluororesin (B) having a melting point of 305°C or lower, the fluororesin (B) having a melting point of 305°C or lower and an inorganic filler (C) such as a silica filler (hereinafter also referred to as the It is called (C) component) after being combined and added, even if (C) component is added, the adhesion strength with copper foil is difficult to decrease, the water resistance is also excellent, and the adhesion strength with copper foil and dielectric properties can be improved. The balance becomes extremely good, and a liquid crystal polyester film having particularly excellent properties can be produced.

The above-mentioned fillers are preferably in granular form. The volume average particle diameter of the filler may be 0.1 μm or more and 10 μm or less, 0.2 μm or more and 5 μm or less, or 0.3 μm or more and 1 μm or less. When the volume average particle diameter of the filler is within the above-mentioned range, the dispersibility in the liquid crystal polyester liquid composition is excellent, so it is preferable. The volume average particle diameter of the filler can be measured by a laser diffraction/scattering particle diameter distribution measuring device.

When the liquid composition of the embodiment contains the inorganic filler (C), the content may be 5% by mass or more and 70% by mass or less, or 20% by mass relative to the total content of the solid content of the liquid composition. The mass % or more may be 50 mass % or less, and may be 30 mass % or more and 45 mass % or less. When the inorganic filler (C) is contained within the above numerical range, the properties of the inorganic filler can be well exhibited. For example, when a liquid composition containing a silica filler is used above the above lower limit value, for example, the dielectric properties of the liquid crystal polyester film to be produced can be improved. Moreover, by using the liquid composition containing a silica filler below the said upper limit, the adhesive strength of the produced liquid crystal polyester film and copper foil can be made favorable.

The liquid composition of the embodiment may contain (A) component, (B) component, and (S) component, and may further contain (C) component. As a preferable example of the compounding ratio of each component in the composition, the content ratio of the aforementioned (A) component is 25% by mass to 40% by mass relative to the total content of the solid content of the liquid composition, (B) ) The content ratio of a component is 25 mass % or more and 40 mass % or less, and the content ratio of the said (C) component is 20 mass % or more and 50 mass % or less can be illustrated. As a preferable example of the compounding ratio of each component in the composition, the content ratio of the aforementioned (A) component is 25 mass % or more and 35 mass % or less with respect to the total solid content content of the liquid composition, and (B ) The content ratio of a component is 25 mass % or more and 35 mass % or less, and the content ratio of the said (C) component is 30 mass % or more and 45 mass % or less can be illustrated. In addition, as an example of a combination of these numerical ranges, for example, as an example of the content ratio of each component, the numerical values exemplified above can be freely combined.

Examples of resins not corresponding to (A) component and (B) component include polypropylene, polyamide, polyester other than liquid crystal polyester, polyphenylene sulfide, polyether ketone, and polycarbonate. , thermoplastic resins other than liquid crystal polyesters such as polyether, polyphenylene ether and its modifications, polyetherimide and other liquid crystal polyesters; elastomers such as copolymers of glycidyl methacrylate and polyethylene; and phenolic resins, For thermosetting resins such as epoxy resins, polyimide resins, and cyanate resins, the content may be 0, preferably 20 parts by mass or less, relative to 100 parts by mass of the liquid crystal polyester.

According to the liquid crystal polyester liquid composition of the embodiment, a film excellent in adhesion strength to copper foil and dielectric properties can be produced.

When the liquid composition of the embodiment contains the component (A), a film having excellent adhesion strength and dielectric properties to copper foil can be produced.

According to the liquid composition of the present embodiment, a film forming method capable of producing a thin film having excellent isotropic properties can be applied. Conventionally, a liquid crystal polyester film can be generally produced by a melt molding method or a solution casting method in which liquid crystal polyester is melted. The melt forming method is a method of forming a film by extruding a kneaded product from an extruder. However, in the film produced by the melt molding method, the liquid crystal polyester molecules are more easily oriented in the film forming direction than in the lateral direction with respect to the extrusion direction, and it is difficult to obtain liquid crystal polyester excellent in isotropy. On the other hand, in the solution casting method, when a film is to be formed without isotropic extrusion, the orientation of the liquid crystal polyester is more likely to be isotropic than that of a liquid crystal polyester film formed by a melt molding method.

According to the liquid composition of the embodiment, since the liquid crystal polyester (A) is soluble in the aprotic solvent (S), a solution casting method can be applied, and a liquid crystal polyester film excellent in isotropy can be produced.

By containing the (B) component, the liquid composition of the embodiment can produce a film having excellent adhesion strength with copper foil, dielectric properties, and water resistance.

Since the liquid composition of the embodiment further contains the component (C), a film having more excellent dielectric properties and water resistance can be produced. Moreover, by containing (C)component in a liquid composition, the outstanding film which is extremely favorable in the balance of adhesion strength with copper foil, dielectric property, and water resistance can be produced.

≪Liquid crystal polyester film≫ The liquid crystal polyester film of the embodiment contains a liquid crystal polyester (A) and a fluororesin (B) having a melting point of 305° C. or lower, and the liquid crystal polyester (A) contains an amide bond. Hereinafter, the liquid crystal polyester film according to one embodiment of the present invention is simply referred to as the "film" of the embodiment.

FIG. 1 is a schematic diagram showing the configuration of a liquid crystal polyester film 10 according to an embodiment.

As a liquid crystal polyester (A), what was demonstrated as said (A) component is mentioned, and its detailed description is abbreviate|omitted here. In addition, the liquid crystal polyester (A) in the state of being formed into a thin film is not soluble in an aprotic solvent due to the change of physical properties through a thin film formation process or the like. The above-mentioned change in physical properties is, for example, an increase in the degree of polymerization.

The liquid crystal polyester (A) preferably contains a structural unit represented by the following formula (A1), a structural unit represented by the following formula (A2), and a structural unit represented by the following formula (A3). (A1) -O-Ar1-CO- (A2) -CO-Ar2-CO- (A3) -X-Ar3-Y- (In the formula, Ar1 represents 1,4-phenylene, 2,6-naphthalenediyl or 4,4'-diphenylene, and Ar2 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthalene diyl, Ar3 represents 1,4-phenylene or 1,3-phenylene, X represents -NH-, Y represents -O- or -NH-).

As a fluororesin (B) whose melting|fusing point is 305 degrees C or less, what was demonstrated as said (B) component is mentioned, and its detailed description is abbreviate|omitted here.

Similar to the liquid composition of the above-described embodiment, the film of the embodiment may contain other components as necessary in addition to the components (A) and (B), for example, a filler, an antioxidant, a heat stabilizer, and an ultraviolet ray. Additives such as absorbers, antistatic agents, surfactants, flame retardants, and colorants, and resins not equivalent to (A) components and (B) components, etc., will not be described in detail here.

It is preferable that the thin film of embodiment contains the said (A) component, (B) component, and an inorganic filler (C). The liquid crystal polyester film containing (A) component, (B) component and (C) component is less likely to cause a decrease in adhesion strength with copper foil, and has a good balance of adhesion strength with copper foil and dielectric properties, And those that are also excellent in water resistance have particularly excellent properties. As an inorganic filler (C), what was demonstrated as said (C) component is mentioned, and the detailed description is abbreviate|omitted here. The inorganic filler (C) is preferably filled with silica.

The content of the various components in the film of the embodiment may be the same as the content of the various components in the solid content of the liquid composition of the embodiment exemplified above.

The thin film of the embodiment can exhibit excellent dielectric properties. The specific conductivity of the thin film of the embodiment at a frequency of 1 GHz is preferably 3.1 or less, more preferably 3.0 or less, more preferably 2.9 or less, and particularly preferably 2.8 or less. Moreover, the specific conductivity of the thin film may be 2.3 or more, 2.4 or more, or 2.5 or more. As an example of the numerical range of the said specific conductivity value of the said thin film, it may be 2.3 or more and 3.1 or less, 2.4 or more and 3.0 or less, 2.5 or more and 2.9 or less, or 2.5 or more and 2.8 or less.

In the thin film of the embodiment, the dielectric loss tangent at a frequency of 1 GHz is 0.005 or less, preferably 0.004 or less, more preferably 0.003 or less, more preferably 0.002 or less, and particularly preferably 0.0015 or less. The dielectric loss tangent of the liquid crystal polyester film may be 0.0003 or more, 0.0005 or more, or 0.0007 or more. As an example of the numerical range of the above-mentioned dielectric loss tangent value of the above-mentioned thin film, it may be 0.0003 or more and 0.005 or less, 0.0005 or more and 0.004 or less, 0.0007 or more and 0.003 or less, 0.0007 or more and 0.002 or less, or it may be It is 0.0007 or more and 0.0015 or less. In addition, the specific conductivity and the dielectric loss tangent of the thin film at a frequency of 1 GHz can be measured by a volumetric method using an impedance analyzer under the conditions described in the examples.

The film of the embodiment is excellent in isotropy. In the film of the embodiment, the value of the molecular orientation degree (MOR) measured by a microwave orientation meter is preferably in the range of 1 to 1.1, preferably in the range of 1 to 1.08, and preferably in the range of 1 to 1.06. More preferably, those in the range of 1 to 1.04 are particularly preferred.

The degree of molecular orientation (MOR) is measured by a microwave molecular orientation meter (eg, MOA-5012A manufactured by Oji Scientific Instruments Co., Ltd.). The microwave molecular orientation meter is a device with different microwave transmission intensities in the orientation direction and the right-angle direction by molecular orientation. Specifically, the sample was irradiated with microwaves having a constant frequency (12 GHz was used), the intensity of the transmitted microwaves, which changed according to the orientation of the molecules, was measured, and the ratio of the maximum value to the minimum value was defined as MOR. The microwave electric field with a certain frequency is related to the interaction between the dipoles constituting the molecules and the inner product of the two vectors. From the anisotropy of the dielectric constant of the sample, the degree of orientation can be known because the intensity of the microwaves changes due to the angle at which the sample is arranged.

The linear expansion coefficient obtained in the temperature range of 50 to 100°C under the condition of a heating rate of 5°C/min for the film of the embodiment is preferably 85 ppm/°C or less, preferably 57 ppm/°C or less. 45ppm/°C or less is more preferable, and 40ppm/°C or less is particularly preferable. Although the lower limit value of the linear expansion coefficient is not particularly limited, it is, for example, 0 ppm/°C or more. Moreover, for example, when a copper foil and a film are laminated, since the linear expansion coefficient of the copper foil is 18 ppm/°C, the linear expansion coefficient of the film of the embodiment is preferably close to this value. In other words, the linear expansion coefficient of the film of the embodiment is preferably 0 ppm/°C or more and 57 ppm/°C or less, preferably 10 ppm/°C or more and 45 ppm/°C or less, more preferably 20 ppm/°C or more and 40 ppm/°C or less. good. When the coefficient of linear expansion differs depending on the direction or location of the film, the higher value is used as the coefficient of linear expansion of the film. The films of the embodiments within the above-mentioned numerical range have a low coefficient of linear expansion and high dimensional stability.

The film of the embodiment can exhibit excellent water resistance. As an index of water resistance, the water absorption rate of the film of the embodiment measured in accordance with JIS K 7209 is preferably 0.8 mass % or less, more preferably 0.5 mass % or less, more preferably 0.4 mass % or less, and 0.3 mass % or less. Mass % or less is particularly preferred. Moreover, the water absorption rate of a film may be 0.05 mass % or more, 0.1 mass % or more may be sufficient, and 0.15 mass % or more may be sufficient as it. As an example of the numerical range of the water absorption value of the film, it may be 0.05 mass % or more and 0.8 mass % or less, 0.1 mass % or more and 0.5 mass % or less, or 0.15 mass % or more and 0.4 mass % or less, It may be 0.15 mass % or more and 0.3 mass % or less.

Although the thickness of the thin film of the embodiment is not particularly limited, the preferred thickness of the thin film for electronic components is preferably 5 to 50 μm, preferably 7 to 40 μm, more preferably 10 to 33 μm, and 15 to 15 μm. ~30μm is particularly preferred.

The production method of the film of the embodiment is not particularly limited, and for example, the liquid composition of the embodiment can be formed into a film. From the viewpoint of being able to produce a film having excellent isotropic properties, the film of the embodiment is preferably produced by the below-mentioned "Method for producing a liquid crystal polyester film".

≪Production method of liquid crystal polyester film≫ The production method of the liquid crystal polyester film of the embodiment includes applying the liquid composition of the embodiment on a support, removing the aprotic solvent (S) from the liquid composition, and obtaining a liquid crystal polyester film. This manufacturing method can be equivalent to a solution casting method.

The liquid composition of the embodiment may be exemplified by the above-mentioned "liquid crystal polyester liquid composition".

The manufacturing method of a liquid crystal polyester film may contain the following steps. The step of coating the liquid crystal polyester liquid composition of the embodiment on the support (coating step). A step (drying step) of removing the aprotic solvent (S) from the coated liquid crystal polyester liquid composition.

The method for producing a liquid crystal polyester film according to the embodiment may include a step of heat-treating the liquid crystal polyester liquid composition or the precursor of the liquid crystal polyester film from which the aprotic solvent (S) has been removed (heat treatment) after the coating step. step).

The production method of the liquid crystal polyester film of the embodiment may include on a support, apply the liquid crystal polyester liquid composition of the embodiment, remove the aprotic solvent (S) from the liquid crystal polyester liquid composition, and perform heat treatment After the liquid crystal polyester film was obtained. According to the heat treatment, the polymerization reaction of the polymer in the liquid crystal polyester liquid composition can be promoted, and the volatilization of the aprotic solvent (S) can be further promoted.

The heat treatment may be combined with the drying step described above. Therefore, the manufacturing method of the liquid crystal polyester film of the embodiment may also include a liquid crystal polyester film obtained by applying the liquid crystal polyester liquid composition of the embodiment on a support and heat-treating.

Moreover, the manufacturing method of a liquid crystal polyester film may further contain the process (separation process) of isolate|separating a support body from the said laminated body. In addition, when a liquid crystal polyester film is used as a laminate, even if it is formed directly on a support, it can be used favorably as a film for electronic components, and therefore, the separation step is an essential step in the production step of the liquid crystal polyester film.

Hereinafter, an example of the manufacturing method of the liquid crystal polyester film of embodiment is demonstrated with reference to drawings.

FIG. 3 is a schematic diagram showing an example of the manufacturing process of the liquid crystal polyester film and the laminate of the embodiment. First, the liquid crystal polyester liquid composition 30 is coated on the support 12 (coating step in FIG. 3A ). The liquid composition is applied to the support by methods such as spin coating, dip coating, spray coating, spin coating, curtain coating, slot coating, and screen printing, and may be suitably Choose a method that enables smooth and uniform coating on the support. Moreover, in order to make the distribution of the filler etc. which can be added to the liquid composition uniform, the operation of stirring the liquid composition may be performed before coating. The viscosity of the liquid crystal polyester liquid composition 30 is not particularly limited, but from the viewpoint of simplification of the coating operation and shortening of the drying time, the viscosity measured by a B-type viscometer at 23°C is 200 mPa･s. More preferably 2000mPa･s or less, preferably 250mPa･s or more and 1500mPa･s or less, more preferably 300mPa･s or more and 1000mPa･s or less.

As the support body 12, a glass plate, a resin film, or a metal foil is mentioned, for example. Among them, resin films or metal foils are also preferred, and copper foils are particularly preferred because of their excellent heat resistance, ease of application of liquid compositions, and ease of removal of liquid crystal polyester films. Examples of polyimide (PI) films sold include "U-PilexS" and "U-PilexR" from Ube Industries Co., Ltd., and "Polyimide" from Toray DuPont Co., Ltd. And "IF30", "IF70" and "LV300" of SKC KORON PI CO., LTD. The thickness of the resin film is usually 25 μm or more and 75 μm or less, preferably 50 μm or more and 75 μm or less. The thickness of the metal foil is usually 3 μm or more and 75 μm or less, preferably 5 μm or more and 30 μm or less, and more preferably 10 μm or more and 25 μm or less.

Next, the aprotic solvent is removed from the liquid crystal polyester liquid composition 30 coated on the support 12 (drying step in FIG. 3B ). The liquid composition from which the aprotic solvent is removed becomes the liquid crystal polyester film precursor 40 to be heat-treated. In addition, the aprotic solvent does not need to be completely removed from the liquid composition, and a part of the aprotic solvent contained in the liquid composition may be removed, or the entire aprotic solvent may be removed. The ratio of the aprotic solvent contained in the liquid crystal polyester film precursor 40 is preferably 50 mass % or less, preferably 3 mass % or more and 12 mass % or less with respect to the total mass of the liquid crystal polyester film precursor. , more preferably 5 mass % or more and 10 mass % or less. When the content of the aprotic solvent in the liquid crystal polyester film precursor is more than the above lower limit value, the concern of lowering the thermal conductivity of the liquid crystal polyester film can be reduced. Moreover, when the content of the aprotic solvent in the liquid crystal polyester film precursor is not more than the above-mentioned upper limit value, the concern of deterioration of the appearance of the liquid crystal polyester film due to foaming during heat treatment and the like can be reduced.

The removal of the aprotic solvent is preferably carried out by evaporating the aprotic solvent, and as this method, for example, heating, decompression, and ventilation may be mentioned, and a combination of these may be used. In addition, the removal of the aprotic solvent may be carried out in a continuous manner or in a vane method. From the viewpoint of productivity or workability, the removal of the aprotic solvent is preferably performed by continuous heating, and preferably performed by continuous heating while ventilating. The removal temperature of the aprotic solvent is preferably a temperature below the melting point of the liquid crystal polyester (A) and the fluororesin (B), for example, 40°C or higher and 200°C or lower. The aprotic solvent removal time can be appropriately adjusted, for example, so that the content of the aprotic solvent in the liquid crystal polyester film precursor becomes 3 to 12% by mass. The time for removing the aprotic solvent is, for example, 0.2 hours or more and 12 hours or less, preferably 0.5 hours or more and 8 hours or less.

After heat-treating the laminate precursor 22 having the support 12 and the liquid crystal polyester film precursor 40 thus obtained, obtaining the support 12 and the liquid crystal polyester film 10 (the liquid crystal polyester film precursor 40 is formed by heat treatment. film) of the laminate 20 (heat treatment step in FIG. 3C). At this time, the liquid crystal polyester film 10 formed on the support was obtained. The heat treatment conditions include, for example, heat treatment at a temperature equal to or higher than the melting point of the liquid crystal polyester (A) and the fluororesin (B) after the temperature rises from the boiling point of the medium -50°C to the heat treatment temperature.

Similar to the removal of the aprotic solvent, the heat treatment can be carried out in a continuous method or in a vane method, but from the viewpoint of productivity or workability, a continuous method is preferred, and the removal of the aprotic solvent is preferred. It is better to continue to perform in a continuous manner afterwards.

Next, by separating the liquid crystal polyester film 10 from the laminate 20 having the support 12 and the liquid crystal polyester film 10, the liquid crystal polyester film 10 as a single layer film can be obtained (FIG. 3D separation step). Separation of the liquid crystal polyester film 10 from the laminate 20 is preferably performed by peeling the liquid crystal polyester film 10 from the laminate 20 when a glass plate is used as the support 12 . When a resin film is used as the support 12 , it is preferable to carry out peeling of the resin film or the liquid crystal polyester film 10 from the laminate 20 . When a metal foil is used as the support body 12, it is preferable that the metal foil is separated from the laminate 20 when the metal foil is removed by etching. When a resin film, particularly a polyimide film, is used as the support, the polyimide film or the liquid crystal polyester film can be easily peeled off from the laminate 20, and a liquid crystal polyester film with good appearance can be obtained. When the metal foil is used as the support, it is not necessary to separate the liquid crystal polyester film from the laminate 20, and the laminate 20 can be used as a metal sheet laminate for a printed wiring board.

According to the manufacturing method of the liquid crystal polyester film of the embodiment, a liquid crystal polyester film excellent in isotropy can be manufactured.

≪Laminate≫ The laminate of the embodiment is provided with a metal layer and the liquid crystal polyester film of the embodiment laminated on the metal layer. FIG. 2 is a schematic diagram showing the structure of a laminate 21 according to an embodiment of the present invention. The laminate 21 includes the metal layer 13 and the liquid crystal polyester film 10 laminated on the metal layer 13 . As for the liquid crystal polyester film 10 provided with the laminate, the above-mentioned examples are exemplified, and the description thereof is omitted here. The metal layer provided with the laminate can be exemplified as a support in the below-mentioned "Method for Producing Liquid Crystal Polyester Film" and "Method for Producing Laminate" described later, and a metal foil is preferred. As the metal constituting the metal layer, copper is preferable from the viewpoint of conductivity and cost, and copper foil is preferable as the metal foil.

Although the thickness of the laminate of the embodiment is not particularly limited, it is preferably 5 to 130 μm, more preferably 10 to 70 μm, and more preferably 15 to 60 μm.

Although the manufacturing method of the laminated body of the embodiment is not particularly limited, the laminated body of the embodiment can be manufactured by the below-mentioned "method of manufacturing the laminated body".

As one embodiment of the present invention, a laminate including a metal layer and a liquid crystal polyester film formed by applying the liquid composition of the embodiment on the metal layer can be provided.

The laminate of the embodiment can be suitably used for film applications for electronic components such as printed wiring boards.

≪Manufacturing method of laminate≫ The method for producing the laminate of the embodiment comprises coating the liquid crystal polyester liquid composition of the embodiment on a support, removing the aprotic solvent (S) from the liquid crystal polyester liquid composition, and forming the liquid crystal polyester liquid composition on the support. After the liquid crystal polyester film, a laminate having the above-mentioned support and the above-mentioned film is obtained.

The manufacturing method of the laminate of the embodiment may include the following steps. The step of coating the liquid crystal polyester liquid composition of the embodiment on the support (coating step). A step (drying step) of removing the aprotic solvent (S) from the coated liquid crystal polyester liquid composition.

The method for producing a laminate of the same embodiment as the method for producing a liquid crystal polyester film may further include, after the above-mentioned coating step, the liquid crystal polyester liquid composition or the liquid crystal polymer obtained by removing the aprotic solvent (S). The step of heat-treating the ester film precursor (heat-treating step).

The manufacturing method of the laminate of the embodiment may also include coating the liquid crystal polyester liquid composition of the embodiment on the support, removing the aprotic solvent (S) from the liquid crystal polyester liquid composition, and heat-treating the liquid crystal polyester in the liquid crystal polyester liquid composition. After the liquid crystal polyester film is formed on the support, a laminate including the support and the film is obtained. According to the heat treatment, the polymerization reaction of the polymer in the liquid composition can be accelerated, and the volatilization of the aprotic solvent (S) can be further promoted.

The heat treatment may be combined with the above drying step. Therefore, the manufacturing method of the laminate of the embodiment may also include, coating the liquid crystal polyester liquid composition of the embodiment on the support, after heat treatment, after forming a liquid crystal polyester film on the support, to obtain a liquid crystal polyester film with the support and A laminate of the aforementioned films.

FIG. 3 is a schematic diagram showing an example of the manufacturing process of the liquid crystal polyester film and the laminate of the embodiment. The manufacturing method of the laminated body illustrated in FIG. 3 is the same as that described in the manufacturing method of the liquid crystal polyester film, except that the above-mentioned separation step ( FIG. 3D ) is not performed, so the description is omitted.

According to the manufacturing method of the laminated body of embodiment, the laminated body which has the liquid crystal polyester film of embodiment can be manufactured.

The present invention has the following matters. <1> A liquid crystal polyester liquid composition comprising a liquid crystal polyester (A) soluble in an aprotic solvent, an aprotic solvent (S) and a liquid crystal polyester having a melting point of 305°C or lower, 280°C or higher and 305°C or lower, A fluororesin (B) which is any one of 290°C or higher, 303°C or lower, and 295°C or higher and 301°C or lower, wherein the liquid crystal polyester (A) contains a structural unit represented by the following formula (A1) and the following formula (A2) A structural unit and a structural unit represented by the following formula (A3). (A1) -O-Ar1-CO- (A2) -CO-Ar2-CO- (A3) -X-Ar3-Y- (wherein Ar1 represents 1,4-phenylene, 2,6-naphthalene di base or 4,4'-diphenylene, Ar2 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthalene diyl, Ar3 represents 1,4-phenylene or 1, 3-phenylene, X represents -NH-, Y represents -O- or -NH-). <2> The liquid crystal polyester liquid composition according to the above <1>, wherein the Ar1 is a 2,6-naphthalenediyl group, the Ar2 is a 1,3-phenylene group, and the Ar3 is a 1,4-phenylene group Phenyl, the aforementioned Y is -O-. <3> The liquid crystal polyester liquid composition according to the above <1> or <2>, wherein the liquid crystal polyester liquid composition contains the liquid crystal polyester (A) and the fluororesin (B) as solid components ), with respect to the total mass of the liquid composition, the content ratio of the solid content is 5 mass % or more and 50 mass % or less. <4> The liquid crystalline polyester liquid composition according to any one of the above <1> to <3>, wherein the liquid crystalline polyester liquid crystalline polyester is The content ratio of (A) is 10 mass % or more and 90 mass % or less, and the content ratio of the fluororesin (B) is 10 mass % or more and 90 mass % or less. <5> The liquid crystal polyester liquid composition according to any one of the above <1> to <4>, which further contains a silica filler. <6> The liquid crystal polyester liquid composition according to the above <5>, wherein the volume average particle diameter of the silica filler is 0.1 μm or more and 10 μm or less, 0.2 μm or more and 5 μm or less, and 0.3 μm or more and 1 μm or less. either. <7> The liquid crystal polyester liquid composition according to the aforementioned <5> or <6>, wherein the liquid crystal polyester (A) The content ratio of the fluororesin (B) is 25 mass % or more and 40 mass % or less, the content ratio of the fluororesin (B) is 25 mass % or more and 40 mass % or less, and the content ratio of the silica filler is 20 mass % or more and 50 mass % or less. . <8> The liquid crystal polyester liquid composition according to any one of the above <1> to <7>, wherein the crystal size of the fluororesin (B) is 2.0×10 ^-8 m or more and 2.9×10 ^-8 m or less, 2.1 × 10 ^-8 m or more, 2.7 × 10 ^-8 m or less, or 2.2 × 10 ^-8 m or more and 2.5 × 10 ^-8 m or less. <9> The liquid crystal polyester liquid composition according to any one of the above <1> to <8>, wherein the fluororesin (B) is selected from the group consisting of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer ( perfluoroalkoxyalkane, PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), ethylene-tetrafluoroethylene copolymer, At least one fluororesin consisting of ethylene-chlorotrifluoroethylene copolymer and polyvinylidene fluoride (PVDF). <10> The liquid crystal polyester liquid composition according to any one of the above <1> to <9>, wherein the volume average particle diameter of the fluororesin (B) is 0.1 μm or more and 30 μm or less, and 0.5 μm or more and 10 μm or less and any one of 1 μm or more and 5 μm or less. <11> The liquid crystal polyester liquid composition according to any one of the above <1> to <10>, wherein the aprotic solvent (S) is N-methylpyrrolidone.

<12> A liquid crystal polyester film comprising a liquid crystal polyester (A) and a fluororesin (B) having a melting point of 305° C. or lower, wherein the liquid crystal polyester (A) contains an amide bond. <13> The liquid crystal polyester film according to the above <12>, wherein the liquid crystal polyester (A) contains a structural unit represented by the following formula (A1), a structural unit represented by the following formula (A2), and the following formula (A3) shows the structural unit. (A1) -O-Ar1-CO- (A2) -CO-Ar2-CO- (A3) -X-Ar3-Y- (wherein Ar1 represents 1,4-phenylene, 2,6-naphthalene di base or 4,4'-diphenylene, Ar2 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthalene diyl, Ar3 represents 1,4-phenylene or 1, 3-phenylene, X represents -NH-, Y represents -O- or -NH-). <14> The liquid crystal polyester film according to the above <13>, wherein the Ar1 is a 2,6-naphthalene diyl group, the Ar2 is a 1,3-phenylene group, and the Ar3 is a 1,4-phenylene group, The aforementioned Y is -O-. <15> The liquid crystal polyester film according to any one of the above <12> to <14>, wherein the content of the liquid crystal polyester (A) is 10% by mass relative to the total content of the liquid crystal polyester film 90 mass % or more, and the content ratio of the said fluororesin (B) is 10 mass % or more and 90 mass % or less. <16> The liquid crystal polyester film according to any one of the above <12> to <15>, which further contains an inorganic filler (C). <17> The liquid crystal polyester film according to the above <16>, wherein the content ratio of the liquid crystal polyester (A) is 25 mass % or more and 40 mass % or less with respect to the total content of the liquid crystal polyester film The content ratio of the aforementioned fluororesin (B) is 25 mass % or more and 40 mass % or less, and the content ratio of the aforementioned inorganic filler (C) is 20 mass % or more and 50 mass % or less. <18> The liquid crystal polyester film according to the above <16> or <17>, wherein the inorganic filler (C) is a silica filler. <19> The liquid crystal polyester film according to any one of the above <12> to <18>, wherein the crystallite size of the fluororesin (B) is 2.9×10 ⁻⁸ m or less. <20> The liquid crystal polyester film according to any one of the above <12> to <19>, wherein the fluororesin (B) is selected from the group consisting of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (perfluoroalkyl vinyl ether); oxyalkane, PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), ethylene-tetrafluoroethylene copolymer, ethylene-chlorine At least one fluororesin consisting of trifluoroethylene copolymer and polyvinylidene fluoride (PVDF). <21> The liquid crystal polyester film according to any one of the aforementioned <12> to <20>, wherein the thickness is 5 to 50 μm, preferably 7 to 40 μm, preferably 10 to 33 μm, more preferably 15 to 30 μm . <22> The liquid crystal polyester film according to any one of the above <12> to <21>, wherein the specific conductivity at a frequency of 1 GHz is 2.3 or more and 3.1 or less, preferably 2.4 or more and 3.0 or less, more preferably 2.5 or more 2.9 or less, more preferably 2.5 or more and 2.8 or less. <23> The liquid crystal polyester film according to any one of the above <12> to <22>, wherein the dielectric loss tangent at a frequency of 1 GHz is 0.0003 or more and 0.005 or less, preferably 0.0005 or more and 0.004 or less, more preferably 0.0007 0.003 or less, more preferably 0.0007 or more and 0.002 or less, and particularly preferably 0.0007 or more and 0.0015 or less. <24> The liquid crystal polyester film according to any one of the above <12> to <23>, wherein the molecular orientation degree (MOR) value measured by a microwave orientation meter is 1 to 1.1, and the range of 1 to 1.08 is Preferably, it is 1-1.06, More preferably, it is 1-1.04. <25> The liquid crystal polyester film according to any one of the above <12> to <24>, wherein the coefficient of linear expansion obtained in the temperature range of 50 to 100°C under the condition of a temperature increase rate of 5°C/min is 0 ppm /°C or more and 57 ppm/°C or less, preferably 10 ppm/°C or more and 45 ppm/°C or less, more preferably 20 ppm/°C or more and 40 ppm/°C or less. <26> The liquid crystal polyester film according to any one of the above <12> to <25>, wherein the water absorption rate measured in accordance with JIS K 7209 is 0.05 mass % or more and 0.8 mass % or less, and 0.1 mass % or more and 0.5 mass % % or less is preferable, preferably 0.15 mass % or more and 0.4 mass % or less, more preferably 0.15 mass % or more and 0.3 mass % or less.

<27> A laminate comprising a metal layer and the liquid crystal polyester film according to any one of <12> to <26> laminated on the metal layer.

<28> A laminate comprising a metal layer and a liquid crystal polyester film formed by applying the liquid crystal polyester liquid composition according to any one of the above <1> to <11> on the metal layer. <29> The laminate according to the above <28>, wherein the liquid crystal polyester film has a thickness of 5 to 50 μm, preferably 7 to 40 μm, preferably 10 to 33 μm, more preferably 15 to 30 μm. <30> The laminate according to the above-mentioned <28> or <29>, wherein the metal layer is a copper foil, and the copper foil is peeled at a peeling speed of 50 mm/min in the direction of 90° with respect to the liquid crystal polyester film. The peel strength (90° peel strength) of the liquid crystal polyester film single-sided copper-clad laminate measured by pulling off is 6.5N/cm or more and 10.0N/cm or less, preferably 7.5N/cm or more and 9.8N/cm or less, preferably It is 7.9 N/cm or more and 9.0 N/cm or less. <31> The laminate according to any one of the above <28> to <30>, wherein the specific conductivity of the liquid crystal polyester film at a frequency of 1 GHz is 2.3 or more and 3.1 or less, preferably 2.4 or more and 3.0 or less, preferably It is preferably 2.5 or more and 2.9 or less, more preferably 2.5 or more and 2.8 or less. <32> The laminate according to any one of the above <28> to <31>, wherein the dielectric loss tangent of the liquid crystal polyester film at a frequency of 1 GHz is 0.0003 or more and 0.005 or less, preferably 0.0005 or more and 0.004 or less, It is preferably 0.0007 or more and 0.003 or less, more preferably 0.0007 or more and 0.002 or less, and particularly preferably 0.0007 or more and 0.0015 or less. <33> The laminate according to any one of the aforementioned <28> to <32>, wherein the molecular orientation (MOR) value of the liquid crystal polyester film measured by a microwave orientation meter is 1 to 1.1, and 1 to 1.08 The range is preferably, preferably 1-1.06, more preferably 1-1.04. <34> The laminate according to any one of the above <28> to <33>, wherein the liquid crystal polyester film is a line obtained in a temperature range of 50 to 100° C. under the condition of a temperature increase rate of 5° C./min The expansion coefficient is 0 ppm/°C or more and 57 ppm/°C or less, preferably 10 ppm/°C or more and 45 ppm/°C or less, more preferably 20 ppm/°C or more and 40 ppm/°C or less. <35> The laminate according to any one of the above <28> to <34>, wherein the liquid crystal polyester film has a water absorption rate of 0.05 mass % or more and 0.8 mass % or less as measured in accordance with JIS K 7209, and 0.1 mass % 0.5 mass % or less is preferable, Preferably it is 0.15 mass % or more and 0.4 mass % or less, More preferably, it is 0.15 mass % or more and 0.3 mass % or less.

<36> A method for producing a liquid crystal polyester film, comprising coating the liquid crystal polyester liquid composition described in any one of the above <1> to <11> on a support, and comprising the liquid crystal polyester liquid composition from the liquid crystal polyester liquid composition A liquid crystal polyester film is obtained after removing the aprotic solvent (S) and performing heat treatment. [Example]

Hereinafter, the present invention will be described in more detail by describing the examples, but the present invention is not limited to the following examples.

<Measurement method>

[Determination of melting point of fluororesin] According to JISK 6935, the melting point of the fluororesin was measured as the value of the endothermic absorption peak of differential scanning calorimetry (DSC).

[Measurement of crystal size of fluororesin] Wide-angle X-ray scattering (WAXS: Wide Anle X-ray Scattering) measurement was carried out using a Nano Viewer manufactured by Rigaku Corporation. The fluororesin powder sample was sandwiched by a bag-shaped polyimide film, and the X-beam size was adjusted to be smaller than the sample size. The wavelength of the X-ray is λ=1.5418 Å, and the measurement is carried out in the range of the diffraction angle 2θ=5° to 30°. X-rays were incident on the fluororesin powder sample in the thickness direction of the polyimide film, and transmission X-ray intensity measurement and WAXS measurement were performed to obtain transmission X-ray intensity A _S and WAXS scattering intensity _IS . The transmission X-ray intensity measurement and WAXS measurement were carried out under the same conditions except for the non-fluorine-containing resin powder, and the background transmission X-ray intensity _AB and WAXS scattering intensity _IB were obtained. The transmitted X-ray intensity correction and background control are performed according to the following formula (1) to obtain the corrected WAXS scattering intensity I _C . I _C =I _S /A _S -I _B /A _B (1)

The measurement of the crystal sub-size by X-ray diffraction is carried out as follows. The crystallite size (Å) of the fluororesin powder is in the Debye ring diffraction absorption peak (diffraction absorption peak having an absorption peak in the range of diffraction angle 2θ=17.93±0.2°) obtained by wide-angle X-ray diffraction measurement. The half-value width (β) of the scattering intensity is calculated by the Scherrer formula of the following formula (2). D=K･λ/βcosθ ･･･(2) In the formula, D is the crystal size, λ is the measured X-ray wavelength, β is the half-value amplitude (radian), θ is the diffraction angle, and K is the Scherrer constant (0.94).

[Measurement of flow start temperature of liquid crystal polyester] Using a flow tester (“CFT-500 model” from Shimadzu Corporation), about 2 g of liquid crystal polyester was filled into a mold with a nozzle of inner diameter 1 mm and length 10 mm In the cylinder, under the load of 9.8MPa (100kg/cm ² ), the liquid crystal polyester was melted while the temperature was raised at a rate of 4°C/min, and the liquid crystal polyester was extruded from the nozzle, and the measurement showed 4800Pa･s (48000P) temperature of viscosity.

[Measurement of volume average particle diameter of PFA fine particles] The volume average particle diameter of PFA was measured by a wet method using a scattering particle size distribution analyzer ("LA-950V2" from HORIBA, Inc.) using water as a dispersion medium.

[Viscosity measurement of liquid crystal polyester solution] The solution viscosity of the liquid crystal polyester solution was measured under the following measurement conditions using a B-type viscometer (“TV-22” from Toki Sangyo Co., Ltd.). Measurement conditions: temperature 23°C, rotor rotation number 20rpm

[Determination of peel strength of single-sided copper-clad laminate of liquid crystal polyester film] Three test pieces of 10mm width were cut out from a single-sided copper-coated liquid crystal polyester film. For each test piece, the liquid crystal polyester film was fixed using an autograph "AG-1KNIS" manufactured by Shimadzu Corporation. ), the copper foil is pulled away at a peeling speed of 50 mm/min in the 90° direction of the liquid crystal polyester film, and the peel strength (90° peel strength) of the single-sided copper-clad plate of the liquid crystal polyester film is measured, and 3 tests are calculated. average of the slices.

[Determination of Linear Expansion Coefficient of Liquid Crystal Polyester Film] Using a thermomechanical analyzer (manufactured by Rigaku, type: TMA8310), the linear expansion coefficient from 50°C to 100°C was measured at a temperature increase rate of 5°C/min.

[Determination of specific conductivity and dielectric loss tangent of liquid crystal polyester film] The copper foil on one side of the liquid crystal polyester film is etched and removed by using the second ferric chloride solution. The obtained single-layer liquid crystal polyester film was melted at 350° C. using a flow tester (“CFT-500 model” from Shimadzu Corporation), and then cooled and solidified to produce a diameter of 1 cm and a thickness of 0.5 cm. lozenges in cm. With respect to the obtained tablet, the specific conductivity and dielectric loss tangent in 1 GHz were measured under the following conditions. ･Measuring method: Volumetric method (Device: Impedance analyzer (Model: E4991A, manufactured by Agilent)) ･Electrode type: 16453A ･Measurement environment: 23℃, 50%RH ･Input voltage: 1V

[Measurement of water absorption rate of liquid crystal polyester film] In accordance with JIS K 7209, the water absorption was measured for the liquid crystal polyester films of Examples 1 to 10 and Comparative Example 1.

[Production Example of Liquid Crystal Polyester (A)] In a reactor equipped with a stirring device, a torque meter, a nitrogen introduction tube, a thermometer and a reflux cooler, 940.9 g (5.0 moles) of 6-hydroxy-2-naphthoic acid and 377.9 g (2.5 moles of acetaminophen) were placed. mol), isophthalic acid 415.3 g (2.5 mol) and acetic anhydride 867.8 g (8.4 mol), after replacing the gas in the reactor with nitrogen, under nitrogen flow, stirring from room temperature for 60 minutes The temperature was raised to 140°C, and reflux was performed at 140°C for 3 hours. Next, the temperature was raised from 150°C to 300°C over 5 hours while distilling off the by-product acetic acid and unreacted acetic anhydride, and after holding at 300°C for 30 minutes, the contents were taken out from the reactor and cooled to room temperature. After pulverizing the obtained solid content with a pulverizer, a powdery liquid crystal polyester (A1) was obtained. The flow start temperature of the liquid crystal polyester (A1) was 193.3°C.

The liquid crystal polyester (A1) was heated from room temperature to 160°C over 2 hours and 20 minutes in a nitrogen environment, followed by heating from 160°C to 180°C over 3 hours and 20 minutes, and after holding at 180°C for 5 hours, solid-phase polymerization was carried out. After post-cooling, the powdery liquid crystal polyester (A2) was obtained after pulverizing with a pulverizer. The flow start temperature of the liquid crystal polyester (A2) was 220°C.

The liquid crystal polyester (A2) was heated from room temperature to 180°C over 1 hour and 25 minutes in a nitrogen environment, and then from 180°C to 255°C over 6 hours and 40 minutes. After the polymerization, it was cooled to obtain a powdery liquid crystal polyester (A). The flow start temperature of the liquid crystal polyester (A) was 302°C.

[Preparation of liquid crystal polyester solution] 8 parts by mass of liquid crystal polyester (A) was added to 92 parts by mass of N-methylpyrrolidone (boiling point (1 atmosphere) 204° C.), and stirred at 140° C. for 4 hours in a nitrogen atmosphere to prepare a liquid crystal polymer. Ester solution (A). The viscosity of the liquid crystal polyester solution was 955 mPa･s.

[Preparation of liquid composition] (Examples 1 to 5) To the liquid crystal polyester solution obtained above, PFA (EA2000 manufactured by AGC, melting point: 300.82) of fluororesin in the amount (solid content) shown in Table 1 was added ℃, crystal particle size: 2.28×10 ^-8 m, volume average particle size: 2 μm), using a stirring and defoaming device (AR-500 from Shinky), the liquid compositions of Examples 1 to 5 were prepared .

(Comparative Examples 2 to 4) To the liquid crystal polyester solution obtained above, silicon dioxide (SO-C2 manufactured by Admatechs, average particle size listed in the catalogue: 0.5 μm) was added in the amount (solid content) shown in Table 2, and a stirring defoaming apparatus ( (Share) Shinky's AR-500), the liquid compositions of Comparative Examples 2 to 4 were prepared.

(Examples 6 to 10) PFA (EA2000 manufactured by AGC, melting point: 300.82°C, crystal size: 2.28) of fluororesin in the amount (solid content) shown in Table 3 was added to the liquid crystal polyester solution obtained above. ×10 ^-8 m, volume average particle size: 2 μm) and silica (SO-C2 manufactured by Admatechs, average particle size listed in the catalog: 0.5 μm), using a stirring deaerator (AR-500 from Shinky) ) to prepare the liquid compositions of Examples 6 to 10.

(Comparative Examples 5 to 10) PFA (9738-JN manufactured by Mitsui Chemours, melting point: 308.68° C., manufactured by Mitsui Chemours, melting point: 308.68° C., crystallized) was added to the liquid crystal polyester solution obtained above in the compounding amount (solid content) shown in Table 4. Sub-dimension: 2.97×10 ^-8 m) and silica (SO-C2 manufactured by Admatechs, the average particle size in the catalogue: 0.5 μm), using a stirring defoaming device (AR-500 of Shinky), prepared The liquid compositions of Comparative Examples 5 to 10. Before addition, PFA (9738-JN manufactured by Mitsui Chemours) was separated with a sieve to prepare an average particle diameter of 10 μm.

[Manufacture of liquid crystal polyester film] The liquid compositions of Examples 1 to 10, the liquid compositions of Comparative Examples 2 to 10, and the liquid crystal polyester solution (A) without the addition of fine particles (Comparative Example 1) were placed on copper foil (JXEFL-V2 manufactured by JX Metals). On the roughened surface with a thickness of 12 μm), to make the thickness of the cast film as shown in Tables 1 to 4, a film tape micrometer applicator (manufactured by Tester Industrial Co., Ltd.) and an automatic coating device (Tester Industrial Co., Ltd.) were used. ), type: PI-1210) after casting, drying at 40° C. under normal pressure (1 atmosphere) for 4 hours, and removing a part of the solvent from the casting film. And after the 2nd casting, after drying the 1st casting under the above-mentioned drying conditions, the 2nd casting and drying are further implemented. The dried film with copper foil was further heated in a hot air oven from room temperature to 310° C. for 4 hours in a nitrogen environment, and the temperature was maintained for 2 hours for heat treatment to obtain the properties of Examples 1 to 10 and Comparative Examples. The copper foil-clad film (liquid crystal polyester film single-sided copper-clad plate) of the films of the respective examples or comparative examples formed from the respective solutions or liquid compositions of Examples 1 to 9. The peeling strength, which is an index of the adhesion strength with the copper foil, was measured for the copper foil-laminated film, and the single-layer liquid crystal polyester film obtained by etching the copper foil from the copper foil-laminated film was measured. Determination of coefficient of expansion (CTE), water absorption, specific conductivity and dielectric loss tangent. The results are shown in Tables 1-4.

Compared with the liquid crystal polyester films of Comparative Examples 5 to 10, the liquid crystal polyester films of Examples 1 to 10 had higher peel strength values and were excellent in adhesion strength with copper foil. This is presumably because the liquid crystal polyester films of Examples 1 to 10 are formed from liquid crystal polyester liquid compositions containing fluororesin PFA (EA2000) having a melting point of 305° C. or lower, because the liquid crystal polyester films of Comparative Examples 5 to 10 The polyester film is formed from a liquid crystal polyester liquid composition containing a fluororesin PFA (9738-JN) with a relatively high melting point.

Compared with the liquid crystal polyester film of Comparative Example 1, the liquid crystal polyester films of Examples 1 to 5 had the same peel strength, and the values of water absorption, specific conductivity, and dielectric properties of dielectric loss tangent were improved. From this, it was found that in the liquid crystal polyester film formed from the liquid crystal polyester liquid composition containing both the liquid crystal polyester (A) and the fluororesin (B) having a melting point of 305° C. or lower, the peel strength, water resistance, and dielectric properties of the liquid crystal polyester film were improved. The balance of electrical properties is good, and it is one that exhibits excellent properties.

The liquid crystal polyester films of Comparative Examples 2 to 4 in which silica was added to the liquid crystal polyester (A) tended to have favorable CTE values, but were poor in improvement in dielectric property values.

The liquid crystal polyester films of Examples 6 to 10 tended to suppress the increase in CTE value more than the liquid crystal polyester films of Examples 1 to 5. In addition, even though the liquid crystal polyester films of Examples 6 to 10 had the same peel strength as those of Examples 1 to 2 or Comparative Examples 2 to 4 having such a high CTE value, the specific electrical conductivity and dielectric loss tangent were lower than those of Examples 1 to 2 or Comparative Examples 2 to 4. The value of the dielectric properties is improved. Moreover, the value of the water absorption rate was also favorable. From this, it was found that the CTE and water resistance of the liquid crystal polyester film formed from the liquid crystal polyester liquid composition containing liquid crystal polyester (A) and having a melting point of 305° C. or lower (B) and further containing silicon dioxide The balance of properties, peel strength, and dielectric properties was good, and it was shown to have excellent properties.

The respective configurations and these combinations in the respective embodiments are examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the gist of the present invention. In addition, the present invention is not limited by each embodiment, but is limited only by the scope of claims (claims).

10: Liquid crystal polyester film 12: Support 13: Metal layer 20, 21: Laminates 22: Laminate Precursors 30: Liquid crystal polyester liquid composition 40: liquid crystal polyester film precursor

Fig. 1 is a schematic view showing the structure of a liquid crystal polyester film according to an embodiment of the present invention. [ Fig. 2] Fig. 2 is a schematic view showing the structure of a laminate according to an embodiment of the present invention. 3A is a schematic view showing a manufacturing process of a liquid crystal polyester film and a laminate according to an embodiment of the present invention. [ Fig. 3B] Fig. 3B is a schematic view showing a manufacturing process of the liquid crystal polyester film and the laminate according to one embodiment of the present invention. [ Fig. 3C ] A schematic diagram showing the production process of the liquid crystal polyester film and the laminate according to one embodiment of the present invention. 3D is a schematic view showing a manufacturing process of the liquid crystal polyester film and the laminate according to one embodiment of the present invention.

Claims (17)

A liquid crystal polyester liquid composition comprising a liquid crystal polyester (A) soluble in an aprotic solvent, an aprotic solvent (S) and a fluororesin (B) having a melting point of 305°C or lower. The liquid crystal polyester liquid composition according to claim 1, wherein the liquid crystal polyester (A) contains an amide bond. The liquid crystal polyester liquid composition according to claim 1 or 2, wherein the liquid crystal polyester (A) contains a structural unit represented by the following formula (A1), a structural unit represented by the following formula (A2), and the following formula ( The structural unit shown in A3), (A1) -O-Ar1-CO- (A2) -CO-Ar2-CO- (A3) -X-Ar3-Y- (In the formula, Ar1 represents 1,4-phenylene, 2,6-naphthalenediyl or 4,4'-diphenylene, and Ar2 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthalene diyl, Ar3 represents 1,4-phenylene or 1,3-phenylene, X represents -NH-, Y represents -O- or -NH-). The liquid crystal polyester liquid composition according to claim 3, wherein the aforementioned Ar1 is a 2,6-naphthalene diyl group, the aforementioned Ar2 is a 1,3-phenylene group, the aforementioned Ar3 is a 1,4-phenylene group, and the aforementioned Y is a -O-. The liquid crystal polyester liquid composition according to any one of claims 1 to 4, wherein the content ratio of the liquid crystal polyester (A) with respect to the total solid content of the liquid crystal polyester liquid composition is: 10 mass % or more and 90 mass % or less, and the content ratio of the aforementioned fluororesin (B) is 10 mass % or more and 90 mass % or less. The liquid crystal polyester liquid composition according to any one of claims 1 to 5, further comprising an inorganic filler (C). The liquid crystal polyester liquid composition according to claim 6, wherein the content ratio of the liquid crystal polyester (A) is 25% by mass or more and 40% by mass relative to the total content of the solid content of the liquid crystal polyester liquid composition. % or less, the content ratio of the fluororesin (B) is 25 mass % or more and 40 mass % or less, and the content ratio of the inorganic filler (C) is 20 mass % or more and 50 mass % or less. The liquid crystal polyester liquid composition according to claim 6 or 7, wherein the inorganic filler (C) is a silica filler. The liquid crystal polyester liquid composition according to any one of claims 1 to 8, wherein the crystallite size of the fluororesin (B) is 2.9×10 ⁻⁸ m or less. The liquid crystal polyester liquid composition according to any one of claims 1 to 9, wherein the fluororesin (B) is selected from the group consisting of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers (perfluoroalkoxyalkanes, PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer At least one fluororesin grouped by polyvinylidene fluoride (PVDF). The liquid crystal polyester liquid composition according to any one of claims 1 to 10, wherein the content of the liquid crystal polyester (A) is 0.01 part by mass relative to 100 parts by mass of the aprotic solvent (S) More than 100 parts by mass or less. The liquid crystal polyester liquid composition according to any one of claims 1 to 11, wherein the aprotic solvent (S) is N-methylpyrrolidone. A liquid crystal polyester film comprising a liquid crystal polyester (A) and a fluororesin (B) having a melting point of 305° C. or lower, wherein the liquid crystal polyester (A) contains an amide bond. The liquid crystal polyester film of claim 13, wherein the liquid crystal polyester (A) contains a structural unit represented by the following formula (A1), a structural unit represented by the following formula (A2), and a structure represented by the following formula (A3) unit, (A1) -O-Ar1-CO- (A2) -CO-Ar2-CO- (A3) -X-Ar3-Y- (In the formula, Ar1 represents 1,4-phenylene, 2,6-naphthalenediyl or 4,4'-diphenylene, and Ar2 represents 1,4-phenylene, 1,3-phenylene or 2,6-naphthalene diyl, Ar3 represents 1,4-phenylene or 1,3-phenylene, X represents -NH-, Y represents -O- or -NH-). A laminate comprising a metal layer, and the liquid crystal polyester film of claim 13 or 14 laminated on the metal layer. A laminate comprising a metal layer and a liquid crystal polyester film laminated on the metal layer and formed by coating the liquid crystal polyester liquid composition according to any one of claims 1 to 12. A method for producing a liquid crystal polyester film, comprising coating a liquid crystal polyester liquid composition according to any one of claims 1 to 12 on a support, and removing the aprotic solvent from the liquid crystal polyester liquid composition (S), a liquid crystal polyester film is obtained after heat treatment.

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